Research on Change of Natural Radionuclide Radiation Above Highways Pavement in Lithuania

Average Equivalent Dose Rate (EDR) caused by natural radionuclide gamma (γ) radiation has been measured above the pavement of the following highways: Vilnius–Panevėžys, Vilnius–Rokiskis, Vilnius–Klaipėda. The estimated EDR values vary from 116 to 142 nSv/h above asphalt concrete pavement and from 79 to 122 nSv/h depending on the composition of soil above the highways sides. Spectrometer research of asphalt concrete and samples of various types of soil have been made. Natural radionuclide specific activity (A, Bq/kg) in asphalt concrete is higher than in clay loam and sandy loam: potassium (40K) and radium (226Ra) – about 3, thorium (232Th) – 4 times.